This invention relates to an ultrasonic probe for use with a puncturing cannula and, more particularly, to an ultrasonic probe having a slot for guiding a puncturing cannula therethrough.
When withdrawing tissue or body fluids from organs in a human body such as liver or kidneys by a suitable puncturing cannula for diagnosis, it has been known to use an ultrasonic probe for guiding the cannula so as to perform a safe puncture by simultaneously observing on a display the objective of the operation, and the movement of the cannula in the body.
Shown in FIG. 1 is a conventional ultrasonic probe having means for receiving a puncturing cannula. The probe includes a substantially rectangular parallelepiped-shaped support member 1 provided with a plurality of ultrasonic transducer elements 2 arranged in at least one row on its bottom surface 1a which will be in contact with the human body. The transducer elements 2 are individually connected to a display (not shown) by a cable 3, as shown in FIG. 1, for showing tomographs of the organ to be contracted and the advancing cannula. The support member 1 is provided with a guide slot 4 extending through the support member 1 from the top surface 1b to the bottom surface 1a. The slot 4 narrows from the top surface 1b to the bottom surface 1a for guiding a cannula to position substantially at the midpoint of the row of transducer elements 2. The height of the member 1 between the surfaces 1a and 1b is normally greater than the width of the surface 1a, from front to back as shown.
An elongated aperture 5 communicating with the guide slot 4 is defined on a side face of the member 1 intersecting rectangularly with the bottom surface 1a and upper surface 1b of the support member 1. By this arrangement, when performing X-ray photography, after the cannula has punctured the objective of the subject, the support member 1 can be removed by a lateral movement on the body surface of the subject without disturbing the cannula.
Moreover, the conventional ultrasonic probe is constructed for use on the surface of the body and for use with a relatively long cannula. It has been found that in the conventional probe the cannula is unstable and difficult to direct with accuracy.
In recent years, the conventional ultrasonic probe has been used internally in examinations to identify, for example, metastasis of cancer of the liver. In these examinations, an incision is made in the abdomen and the probe is inserted into the abdomen and into actual contact with the liver and other organs which may be affected. In order to secure the proper alignment of the row of transducer elements 2 on the bottom surface 1a of the probe, a portion of the probe often must be inserted between the costae (ribs) and the liver or other organs.
Due to the height and weight of the conventional probe, undue pressure may be exerted not only on the organ under examination, but on other organs in contact with organs under examination.